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New Metastable Phase of Bismuth (III) Selenide: Crystal Structure and Electrical Properties
Author(s) -
Serebryanaya Nadezhda,
Buga Sergey,
Bagramov Rustem,
Pahomov Ilya,
Eliseev Nikolai,
Blank Vladimir
Publication year - 2020
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.202000145
Subject(s) - bismuth , materials science , orthorhombic crystal system , differential scanning calorimetry , crystallography , metastability , crystal structure , selenide , electrical resistivity and conductivity , band gap , amorphous solid , annealing (glass) , analytical chemistry (journal) , chemistry , thermodynamics , selenium , metallurgy , physics , optoelectronics , organic chemistry , chromatography , electrical engineering , engineering
Using high‐pressure–high‐temperature treatment at P = 4–7.7 GPa; T = 1373–1473 K with subsequent quenching, a new metastable phase of bismuth selenide ( m ‐Bi 2 Se 3 ) is synthesized and its crystal structure, electrical resistivity, and annealing at heating are investigated. Using X‐ray powder diffraction, and analogy with high‐pressure structures of the rare‐earth element sesquichalcogenides, the crystal structure of the new metastable phase of m ‐Bi 2 Se 3 is determined as an orthorhombic distorted cation‐deficient structure of the Th 3 P 4 type with the Fdd2 space group and Z = 10.66. The unit‐cell dimensions are: a = 13.4660(7) Å, b = 12.7772(7) Å, c = 9.0896(5) Å. The density of m ‐Bi 2 Se 3 (7.47 g cm −3 ) is slightly less than the initial rhombohedral phase of Bi 2 Se 3 , but the coordination number (CN) = 8 is higher than CN = 6 of the initial phase. The period of stability under ambient conditions of the new m ‐Bi 2 Se 3 phase is only about 2 months. After 300 °C annealing, m ‐Bi 2 Se 3 completely returns to the initial layered structure, and differential scanning calorimetry confirms that the reverse transformation as well as the direct transition occur through an amorphous state. The new phase is a narrow bandgap semiconductor with the energy gap of about 80 meV.